Electrochemical and quantum chemical studies of ethylene glycol and diethylene glycol monoethyl ether on corrosion of carbon steel pipelines in acidic medium

The influence of ethylene glycol (EG) and diethylene glycol monoethyl ether (DGME) were investigated as corrosion inhibitors of API X80 in 1 M HCl solution using Tafel polarization and electrochemical Impedance spectroscopy techniques. Potentiodynamic polarization curves indicated that EG and DGME behave as mixed-type inhibitors. EIS measurements showed that DGME increased of the transfer resistance with increasing inhibitor concentration whereas EG increased it at high concentrations. The inhibitors were adsorbed on the steel surface according to the Langmuir adsorption isotherm model. Relationship between molecular structure and their inhibition efficiency was elucidated by quantum chemical calculations using the density functional theory (DFT).

Keywords:

carbon steel pipeline , quantum chemical , corrosion inhibitor